Assignment 5-RADIOSS Interfaces & Study of Effect of Notches Challenge

OBJECTIVE:

To create mesh of the given bumper ssembly with a mesh size of 6mm.

PROCEDURE:

• IMPORT:
• Given model is imported to Hyperworks using import model option.

• The given model is viewed in topo mode to view the surface edges.

• Geometry Cleanup :

• Since the topo mode view shows the surface irregularities in the imported model, it should be cleared before meshing of the model.
• The geometric cleanup of the imported model is done using the follwing tools:
• For missing surfaces, filler surf option under quick edit tab is used
• For Disconnected edges, toggle edge option under quick edit tab is used.

• MESHING:
• After the cleanup is finished and each simple surfaces are selected to obtain proper mesh.
• The meshing is done by using automesh tool under 2-D tab with elements size as 6mm and element type as mixed.
• The meshing of each component is done component wise.

• Similarly meshing is progressed into adjacent surfaces to mesh the whole model and meshing is completed to obtain mesh as shown below:

• CONCLUSION:
• Hence carried out geometry cleanup operation on the given model.
• Meshing performed on the each component with elements size under the given quality criteria of 6mm.

OBJECTIVE:

To perform RADIOSS analysis on the given Crush Tube under given conditions and different notch locations.

Case 1:

Running simulation on the model as it is without changing any formulations.

IMPORT:

The given rad file is imported using import option.

To create TH/Part, under solver broswer , new TH -> PART option is selected and all the 4 components are selected.

Simulation is performed using RADIOSS option under analysis tab, and the OUT file is viewed to check stability of the system.

From the OUT file,

• energy error = 0% to -4.6%
• mass error = 0.00

Since the energy and mass error are within the acceptable range, the model is stable.

Now the time for simulation and number of cycles taken to complete the simulation is also noted from the OUT file.

Plotting the energy curves using Hypergraph 2-D with the help of T01 File:

Resultant of the rigid wall forces is plotted and it can be observed that the rigid wall force rises with the deformation in the crush tube. After 20ms there is a steep rise in the force and finally reduces to zero when the tube is fully deformed and remains zero till end of the simulation.

The internal energy of the system keeps rising till the tube is fully deformed and then remains roughly constant after 26ms till end of the simulation.

Contact energy of the system also rises due to deformation, and at a point rises with a steep slope till the tube is fully deformed, then reduces and remains constant till end of the simulation.

Animation and Contour plot of the simulation is obtained under Hyperview using the h3d file saved in the directory:

It is observed from the animation that, the deformation of the tube under the action of force starts at the upper notch. on further laoding, the upper notch gets fully bend, which on further loading, bending of the lower notch takes place. After both the notch region get bend, the upper part of the tube bends in a similar trend as that occured in the lower part of the crush tube.

The crush tube gets fully deformed to a stage as shown below:

It is observed that, Von Mises stress values reaches a value upto a maimum of 0.5865N/mm2.

Case 2:

Changing value of iinacti to 6 and run the simulation:

Initially the given rad file is imported using import option.

Inorder to change flag for inactivation of stiffness, Solver browser is opened under View>browsers>Hypermesh>Solver

Under solver browser, INTER collector is expanded under which TYPE 7 is selected to modify the value of inacti

Inacti = 6 implies the simulation will consider varying thickness but with initial penetration computation.

To create TH/Part, under solver broswer , new TH -> PART option is selected and all the 4 components are selected.

Simulation is performed using RADIOSS option under analysis tab, and the OUT file is viewed to check stability of the system.

From the OUT file,

• energy error = 0% to -4.6%
• mass error = 0.00

Since the energy and mass error are within the acceptable range, the model is stable.

Now the time for simulation and number of cycles taken to complete the simulation is also noted from the OUT file.

Plotting the energy curves using Hypergraph 2-D with the help of T01 File:

Resultant of the rigid wall forces is plotted and it can be observed that the rigid wall force rises with the deformation in the crush tube. After 20ms there is a steep rise in the force and finally reduces to zero when the tube is fully deformed and remains zero till end of the simulation.

The internal energy of the system keeps rising till the tube is fully deformed and then remains roughly constant after 26ms till end of the simulation.

Contact energy of the system also rises due to deformation, and at a point rises with a steep slope till the tube is fully deformed, then reduces at time after 26ms and remains constant after 27.5ms till end of the simulation.

Animation and Contour plot of the simulation is obtained under Hyperview using the h3d file saved in the directory:

In this case also, It is observed from the animation that, the deformation of the tube under the action of force starts at the upper notch. on further laoding, the upper notch gets fully bend, which on further loading, bending of the lower notch takes place. After both the notch region get bend, the upper part of the tube bends in a similar trend as that occured in the lower part of the crush tube.

The crush tube gets fully deformed to a stage as shown below:

The crush tube deforms till 27ms and then afterwards the tube is slightly released and rises from the rigid wall.

It is observed that, Von Mises stress values reaches a value upto a maimum of 0.69N/mm2.

Case 3:

Create the type 11 contact and run.

initially the given rad file is imported using import option.

To create Type11 contact, under the model browser, new contact is created and Type 11 is selected as the card image.

Recommended properties for Type7 contact itself is used for type11 contact.

To create TH/Part, under solver broswer , new TH -> PART option is selected and all the 4 components are selected.

Under Type 11, both slave and master components are selected.

Simulation is performed using RADIOSS option under analysis tab, and the OUT file is viewed to check stability of the system.

From the OUT file,

• energy error = 0% to -2.6%
• mass error = 0.00

Since the energy and mass error are within the acceptable range, the model is stable.

Now the time for simulation and number of cycles taken to complete the simulation is also noted from the OUT file.

Plotting the energy curves using Hypergraph 2-D with the help of T01 File:

Resultant of the rigid wall forces is plotted and it can be observed that the rigid wall force rises with the deformation in the crush tube. After 20ms there is a steep rise in the force and finally reduces to zero when the tube is fully deformed and remains zero till end of the simulation.

Compared to above 2 cases, there is an increase in resultant force value and also, the peek force occurs at around 26ms, 1 ms vefore the above 2 cases.

The internal energy of the system keeps rising till the tube is fully deformed and then remains roughly constant after 26ms till end of the simulation.

Contact energy of the system also rises due to deformation, and at a point rises with a steep slope till the tube is fully deformed, then reduces at time after 26ms and remains constant after 27.5ms till end of the simulation.

In this case, the contact energy is reduced upto 1170mJ rather than around 2100mJ in other 2 cases.

Animation and Contour plot of the simulation is obtained under Hyperview using the h3d file saved in the directory:

SImilar to the above cases, in this case also, It is observed from the animation that, the deformation of the tube under the action of force starts at the upper notch. on further laoding, the upper notch gets fully bend, which on further loading, bending of the lower notch takes place. After both the notch region get bend, the upper part of the tube bends in a similar trend as that occured in the lower part of the crush tube.

The crush tube gets fully deformed to a stage as shown below:

The crush tube deforms till 27ms and then afterwards the tube is slightly released and rises from the rigid wall.

It is observed that, Von Mises stress values reaches a value upto a maimum of 0.644N/mm2.

Case 4:

Remove both notches and remove boundary condition on rigid body node then run.

initially the given rad file is imported using import option.

To remove the notches in the Tube, Node edit option under Geometry tab is used. Align node option is used to remove the notches on the tube porfile.

To remove the rigid wall boundary condition, BCS collector under solver browser is viewed.

All DOF conditions are removed to follow the given condition.

After all conditions are specified, TH/PART is created and all components are selected.

Simulation is performed using RADIOSS option under analysis tab, and the OUT file is viewed to check stability of the system.

From the OUT file,

• energy error = 0% to -3.7%
• mass error = 0.00

Since the energy and mass error are within the acceptable range, the model is stable.

Now the time for simulation and number of cycles taken to complete the simulation is also noted from the OUT file.

Plotting the energy curves using Hypergraph 2-D with the help of T01 File:

Resultant of the rigid wall forces is plotted and it can be observed that the rigid wall force rises with the deformation in the crush tube. After 20ms there is a steep rise in the force and finally reduces to zero when the tube is fully deformed and remains zero till end of the simulation.

Compared to above 3 cases, there is an decrease in resultant force value and also the peek force occurs at around 27.5ms.

The internal energy of the system keeps rising till the tube is fully deformed and then remains roughly constant after 26ms till end of the simulation.

Internal energy curve reaches the peek value after 27.5ms which is different from all the above cases.

Contact energy of the system also rises due to deformation, and at a point rises with a steep slope till the tube is fully deformed, then reduces at time after 27.5ms and remains constant after 29ms till end of the simulation.

In this case, the contact energy is increased upto 1580mJ.

Animation and Contour plot of the simulation is obtained under Hyperview using the h3d file saved in the directory:

Since there is no notch in the above crash tube, the deformation in the tube starts from the bottom of the tube and the tube continues to deform till the top.

The crush tube deforms till 27ms and then afterwards the tube is slightly released and rises from the rigid wall.

Stress value reaches upto a value of 0.6628N/mm2.

Case 5:

Create a new notch in the middle ,select the whole section and run.

initially the given rad file is imported using import option.

To create the notch in the middle, Align node option under node edit tool is used.

Assigning recomended Type 7 Formulations:

Recommended formulations for Type7 contact is defined.

After all conditions are specified, TH/PART is created and all components are selected.

Simulation is performed using RADIOSS option under analysis tab, and the OUT file is viewed to check stability of the system.

From the OUT file,

• energy error = 0% to -6%
• mass error = 0.00

Since the energy and mass error are within the acceptable range, the model is stable.

Now the time for simulation and number of cycles taken to complete the simulation is also noted from the OUT file.

Plotting the energy curves using Hypergraph 2-D with the help of T01 File:

Resultant of the rigid wall forces is plotted and it can be observed that the rigid wall force rises with the deformation in the crush tube. After 20ms there is a steep rise in the force and finally reduces to zero when the tube is fully deformed and remains zero till end of the simulation.

Compared to above cases, there is an increase in resultant force value and also, the peek force occurs at around 26ms, 1 ms before the first 2 cases.

The internal energy of the system keeps rising till the tube is fully deformed and then remains roughly constant after 25ms till end of the simulation.

Contact energy of the system also rises due to deformation, and at a point rises with a steep slope till the tube is fully deformed, then reduces at time after 25ms and remains constant after 26ms till end of the simulation.

In this case, the contact energy is increased upto 3300mJ.

Animation and Contour plot of the simulation is obtained under Hyperview using the h3d file saved in the directory:

The animation of the simulation results shows that, the initial benidng happens at the notch in the middle. Then the derformation of the tube occurs at the bottom half. After the bottom half is deformed, the deformation occurs at the top half.

The crush tube deforms till 27ms and then afterwards the tube is slightly released and rises from the rigid wall.

Stress value reaches upto a value of 0.6164N/mm2.

Case 6:

Create a new notch with nodes only from opposing 2 faces and run.

Initially the given rad file is imported using import option.

To create notches on opposite faces, Align node option under node edit tool is used.

Assigning Recommended formulations of TYPE 7 contact:

After all conditions are specified, TH/PART is created and all components are selected.

Simulation is performed using RADIOSS option under analysis tab, and the OUT file is viewed to check stability of the system.

From the OUT file,

• energy error = 0% to -7%
• mass error = 0.00

Since the energy and mass error are within the acceptable range, the model is stable.

Now the time for simulation and number of cycles taken to complete the simulation is also noted from the OUT file.

Plotting the energy curves using Hypergraph 2-D with the help of T01 File:

Resultant of the rigid wall forces is plotted and it can be observed that the rigid wall force rises with the deformation in the crush tube. After 20ms there is a steep rise in the force upto 1400N/mm2 and finally reduces to zero when the tube is fully deformed and remains zero till end of the simulation.

Compared to above cases, there is an increase in resultant force value and also, the peek force occurs at around 26ms, 1 ms before the first 2 cases.

The internal energy of the system keeps rising till the tube is fully deformed and then remains roughly constant after 26ms till end of the simulation.

Contact energy of the system also rises due to deformation, and at a point rises with a steep slope till the tube is fully deformed, then reduces at time after 27ms and remains constant after 27.5ms till end of the simulation.

In this case, the contact energy is increased upto 3800mJ.

Animation and Contour plot of the simulation is obtained under Hyperview using the h3d file saved in the directory:

The animation of the simulation results shows that, the initial benidng happens at the notch. Then the derformation of the tube occurs at the bottom part of the tube after notch. After the bottom is deformed, the deformation occurs at the top part.

In this case, the face with notch bends inwards while adjacent plane surfaces bends outwards initiially at the start of deformation.

The crush tube deforms till 27ms and then afterwards the tube is slightly released and rises from the rigid wall.

Stress value reaches upto a value of 0.6164N/mm2.

CONCLUSION:

The deformation in the crash tube with & wothout notches and different types of contact is simulated and following conclusions are made:

1) Internal energy increases with deformation of the crash tube and remains constant once the tube is fully deformed.

2) With crash tube having notches, the deformation in the tube is initiated at nnotch area further deforming the whole tube.

3) Tube having multiple notches, the notch which is farther away from the rigid wall gets deformed first, follwed by the other.

4) for a crash tube with no notches, the deformation is found to start from the point of contact of the tube with the rigid wall.

5) Energy plots under different cases showed similar trends but with different stress, force and energy values.